Vehicle headlamps are presently made in roughly two pieces. There is a reflector section which includes the essential optical reflector, and other housing features such as a lens cover, mounting and aiming hardware. The second element is the replaceable light source, or capsule that latches in place in the reflector. The pattern of light that appears on the road is the result of both elements, and great effort has been made in improving both elements. Further demands for smaller, more compact headlamps, requires even more control in the manufacture of the reflector and the lamp capsule. In a 10 centimeter high headlamp, the misplacement of the light source with respect to the reflector by as little as quarter of a millimeter can have a bothersome effect on the beam pattern at 100 meters distance. Such misdirection of the beam pattern is one cause of the unpleasant glare drivers experience with oncoming vehicles. There is then a need to improve the accurate location of the light source with respect to the reflector in vehicle headlamps.
Previously, the reflector passage, where the lamp capsule is inserted has been defined along with its various coupling features by the exterior side mold wall. It is common in plastic molding to experience variations in the process, resulting in variations in the final product. Such variations as wall thickness, and surface location can occur due to wear in the mold parts, misplacement between the mold parts, variations in the mold material, flashing and other molding defects. The result here is an irregular variation in the dimensions between the inside optical surface, and the exterior surface. This variation leads to irregular axial (Z direction) location of the light source. There is then a need for a headlamp system that prevents variations in the molding process from effecting the axial positioning of the lamp.
In the past, the reflector and lamp capsule were manufactured with a small, but nonetheless, real tolerance gap measured radially between reflector passage diameter, and the lamp capsule diameter. This radial wiggle room allowed the capsule to be inserted into the back of the reflector. In the final coupling, an O-ring seal filled and sealed this gap or wiggle room. The O-ring then acted to finally position the lamp capsule. Nonetheless, due to manufacturing variations, flashing on the seal, flashing on the seal surfaces, too little grease, inaccurate seal pinching, and over or under pressing of the seal, the capsule could be twisted or displaced radially (X, Y directions) from the proper lamp axis direction. This type of variation leads to irregular beam pointing. There is then a need for a headlamp system that prevents variations in the radial positioning of the lamp capsule.